486 EXPERIMENT STATION RECORD. 



make the humming sound which is characteristic of Culex, and are, 

 therefore, often present in rooms without being suspected. 



The author discusses at some length the relationship of agriculture 

 to malaria, and states his belief that the plowing of new soil does not 

 contribute to the spread of malaria. 



The fatal effect of green sorghum, R. S. Hiltner {Nehraska Sta. 

 Bui. 63, pp. 71-6%). — The use of sorghum as a forage plant in the 

 State is becoming more extensive, and with its increase in importance 

 for this purpose the number of deaths caused by feeding it increases. 

 During the past year 144 fatal cases in cattle were reported. 



The work reported in the present bulletin was undertaken for the 

 purpose of determining, if possible, the nature and cause of these cases 

 of poisoning. Frequent reports are made of bloat caused b}" the use 

 of sorghum for forage. It has been supposed in some cases that the 

 cause of death from using sorghum was to be found in the presence of 

 parasitic fungi on the leaves of the plants. In a numl)er of instances 

 it has been believed b}^ stockmen that plants were maliciously poisoned 

 with strychnine, Paris green, or arsenic. Analyses made by the station 

 of plants thus suspected indicated no trace of any such poison. Another 

 suggestion made to explain poisoning ))y sorghum is that the plant 

 takes up an unusual quantity of potassium nitrate during certain sea- 

 sons or in certain localities. A number of samples analyzed indicated 

 only a trace of nitrates. The most commonly believed theory for the 

 explanation of poisoning by sorghum is that the plant under certain 

 conditions develops a poisonous principle. The chemical department 

 of the station undertook an investigation of this matter. In reports 

 from stockmen it was noted that the sj^mptoms were nearly uniform 

 in all parts of the State and that the poisoning was not confined to 

 animals of any particular age. 



Samples of sorghum which had caused the death of cattle were 

 analyzed in a fresh green condition and also after drying. Aqueous 

 extracts were made and tested for chemical poisons, but none were 

 found. No chemical compound was discovered which could be con- 

 sidered poisonous. It is of importance to note in this connection that 

 the nitrogen content of the samples which were analyzed was not above 

 the average. The opinion is somewhat widespread that the second 

 growth of sorghum is more dangerous than the tirst growth. This 

 may have been the experience of stockmen in some localities, but when 

 all cases which have been re[)orted from different parts of the State 

 are considered it is found that the lirst growth is not alwa3's harmless 

 and the second growth is not always poisonous. The majority of cases 

 of poisoning i-eported were due to eating the second growth of sor- 

 ghum. It should l)e stated, however, that the tirst growth is not fed in 

 a green state to the same extent as the second growth, and this fact may 

 account for the more extensive poisoning from second-growth plants. 



